All managers have been excellent in my experience. There is a robust formal review process and most people are very happy to give/receive feedback whenever asked. "(Constructive) feedback is a gift" my current manager tells me.
All managers are extremely good mentors, with a strong culture of developing each other during engagements. The business is very flat, meaning people of all levels are easily accessible and always happy to help out. They have a very open performance review system, and a culture of open feedback is strongly encouraged.
Managers are really available and generally have time for lower level consultants.
Work very closely with managers on projects and there is a strong focus on development through formal mentor programs and Manager KPI's and informal focus on improve work and learning new things